Modify admin guide NSX extension operations
Modify admin guide NSX extension operations

To reflect OSC commands due to Neutron client deprecation

Partially Implements: blueprint use-openstack-command

Change-Id: I9cf224bf9a921c098fa3714812d58569dc4f8278

openstack/openstack-manuals,openstack/openstack-manuals,openstack/openstack-manuals,openstack/openstack-manuals